Yellow Wood Sorrel is, at least in my mowed lawn, a short little plant that goes nearly unnoticed unless I'm looking for the little yellow flowers.

I was glad I gave up on trying to eradicate all of my weeds when I found this tiny Phaon Crescent Butterfly getting a sip of nectar from it.

Here's how it looks where it's thickest in my lawn. It fills in the drought caused bare spots with a bit of green at least.

There's a honeybee on the little Yellow Wood Sorrel flower in the middle of the picture: